1. a brass musical instrument similar to a tuba but smaller and higher in pitch, with a conical bore and typically four valves

Examples

• She played the euphonium in the school marching band.
• The euphonium section provided rich, warm tones to the brass ensemble.
• He practiced scales on his euphonium every evening.
• The euphonium solo was the highlight of the concert.
• Learning to play the euphonium requires strong breath control.
• The band director assigned him to euphonium because of his musical ability.